1. Field of the Invention
This invention is directed to tampon pledgets and, more particularly, to tampon pledgets having improved absorbency and expansion characteristics to provide improved by-pass leakage protection.
2. Description of the Related Art
Absorbent catamenial tampons have long been known in the art. Most currently available tampon pledgets are compressed into a substantially cylindrical form from a generally rectangular pad of absorbent material, or a mix of absorbent and non-absorbent material. In use, the tampon pledget is inserted into a vagina of a female. As blood or other body fluids contacts the compressed tampon pledget, the fluid is absorbed and the pledget re-expands toward its pre-compressed size to capture the fluid that otherwise would flow from the vagina during menstruation. One key measure of tampon pledget performance is leakage protection. Most leakage is attributed to a “by-pass” of menstrual fluid. By-pass occurs when the menses travels along the length of the vaginal cavity without contacting the tampon pledget inserted therein. Tampon leakage typically ranges from about fifteen percent to twenty percent (15% to 20%) incidence of tampon leakage for all sizes (e.g., absorbency) of tampons.
The inventors have found that such by-pass is generally due to a less-than-optimal fit of the tampon pledget within the vagina cavity. The propensity of any commercially-produced tampon to leak is highly unpredictable due to, for example, differing manufacturing processes for fabricating tampons as a mass-marketed product and to wide anatomical variations in the vaginal cavity of women using the tampons. Both magnetic resonance imaging (MRI) analysis of actual users as well as ION simulations (anthropometrically correct simulation devices) indicate that a higher likelihood of by-pass leakage exists when the tampon pledget is inserted too high into the vaginal cavity and angled to either the right or left side of the fomices of the vagina. For example, in analyzing the MRI and ION simulation results the inventors have discovered that high placement of the tampon pledget within the vaginal cavity typically causes menstrual fluid from the cervical os (e.g., location where the menstrual fluid exits the uterus) to contact the inserted tampon pledget at approximately a mid or half-way point of a total length of the tampon pledget. As should be appreciated, it is generally preferred that the menstrual fluid contact the tampon pledget at top portion of the pledget's total length to maximize absorbency. As such, contacting the tampon pledget at the mid or half-way point causes the tampon pledget to absorb menstrual fluid less efficiently. For example, some MRI tests have shown that when placed relatively high in the vaginal cavity only a bottom portion of the tampon pledget absorbs fluid while a top portion of the tampon pledget remains relatively unsaturated. The inventors have observed this less than preferred absorption especially pronounced during “light flow” days of the menstrual cycle of female subjects.
As noted above, tampon pledgets are typically compressed and set either during manufacture or placement of the tampon pledget within an applicator barrel. When exposed to moisture and fluids within the body of a user (e.g., menstrual fluid), fibers of the tampon pledget expand. Conventional tampon pledget designs attempt to control expansion such that the expanding tampon pledget conforms to contours of the wearer's body. For example, it is typically a goal that the expansion significantly conform to a portion of the vaginal cavity to prevent by-pass leakage in pathways around the expanding tampon pledget. To date, efforts to control by-pass leakage have been somewhat successful. However, improvement in by-pass leakage protection is still desired. For example, the inventors have realized that since the vaginal cavity has greater elasticity than conventional tampon pledgets, the pledget tends to open up or stretch the width of the vaginal cavity contributing to the formation of by-pass leakage channels.
Given the above-described problems with conventional tampon pledgets, it is contemplated that users would prefer tampon products with improved expansion and absorption capabilities to substantially minimize, if not avoid, by-pass leakage. Accordingly, it has been discovered that there is a continuing need for an improved tampon pledget design and, in particular, for a tampon pledget design that has greater absorbency and expansion capabilities particularly in a radial direction.